While most U.S. adults get plenty of protein in their diets, the 2020-2025 Dietary Guidelines for Americans recommend shifting the food sources of proteins we consume for optimal health. For example, while average intake of total protein foods is at or above recommendations, average seafood intake is below recommendations. Intake of legumes is also low.

“Any protein source will meet one’s protein needs,” says cardiologist Dariush Mozaffarian, director of the Food is Medicine Institute at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University, “so it’s what comes with the protein that matters.” 

A low-sodium food, for example, is a healthier source of protein than a saltier option, and a plant protein source, which also provides fiber, vitamins, minerals, and phytochemicals, is a better choice than a slice of bologna.

All proteins are built from just 20 amino acids. The body can manufacture 11 of these, leaving just nine that we have to get from food. These “essential” amino acids are found in animal foods (meats, poultry, fish/seafood, dairy, eggs) as well as in plant foods (particularly legumes, nuts, seeds, and some grains). Animal foods contain all nine of the essential amino acids (what used to be called “complete” proteins). Some plant foods contain all nine (for instance, soy, quinoa, chia seeds, and buckwheat), but most other plant foods are low in at least one of the essential amino acids (sometimes referred to as “incomplete” proteins).

Health and nutrition experts recommend eating more plant foods and less animal products. This will not create a problem with protein intake. In fact, it is possible to meet all protein needs without eating any animal products at all, as long as you eat a varied diet that includes all kinds of plant proteins, including legumes, whole grains, and nuts/seeds.

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While it used to be thought that “incomplete” plant proteins needed to be combined at each meal to create a complete protein source, it is now understood that meeting all essential amino acid requirements within a single day is sufficient.

“Given the variety of plant foods available in the modern diet, no one really needs to worry about matching different plant sources of protein,” says Mozaffarian, “unless their diet is very regimented and limited to just a few specific plants.” Still, complete combinations of plant proteins have evolved over time in every culture, including rice and beans, pita and hummus, and even peanut butter on bread.

Replacing some animal proteins with plant proteins is not only associated with positive health outcomes, it’s a better choice for the environment. Red meat production in particular requires large amounts of water and energy and creates high levels of greenhouse gas emissions. 

“Some meat-eaters are choosing to decrease their intake, frequently for multiple reasons: the environment, sustainability, or health,” says Alice H. Lichtenstein, senior scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging and the Stanley N. Gershoff Professor of Nutrition Science and Policy at the Friedman School. “In response, the market for plant-based meat substitutes is booming. While in some ways these products are better for the environment, be aware that they are highly processed and may have a nutrient profile not all that dissimilar to meat (including added saturated fat) and may be even higher in sodium.” 

Plant-based “meats” can be useful options, but swapping red meat for legumes, nuts, seeds, and whole grains is a better way to cut back on red meat intake, improve diet quality, and help the environment.

This article originally appeared in the Tufts Health & Nutrition Letter, published each month by the Friedman School of Nutrition Science and Policy.